Auxiliary control means for aircraft



May 8, 1951 w. l. TIN DALL 2,552,073

Filed Feb. 14, 1947 Fig. 3

AUXILIARY CONTROL MEANS FOR AIRCRAFT 2 Sheets-Sheet 1 William B. Tindolfl INVENTOR.

HI PATENT ATTORNEY May 8, 1951 w. l. TINDALL 73 AUXILIARY CONTROL MEANS FOR AIRCRAFT Fil ed'Feb. 14, 1947 2 Sheets-Sheet 2 William I. Tindull Fig. 7 INVENTOR.

Patented May 8, 1951 UNITED STATES AUXILIARY CONTROL MEANS FOR AIRCRAFT Application February 14, 1947, Serial No. 728,592

OFFICE 16 Claims. 1 The present invention relates generally to aircraft control and more particularly to control surfaces adapted for both the longitudinal and lateral control of aircraft and like vehicles.

2 with respect thereto as the auxiliary surfaces are extended into operative position. These auxiliary surfaces are such that the may be extended upwardly and rearwardly with respect to In view of the decided aerodynamic advantages 5 the trailing edge of the wing from a retracted of high lift flaps for take-off and landing purposition within the upper surface thereof and poses, their use is now quite general, particularly are adapted to be efficiently supported in' their in the operation of medium and large aircraft. upwardly and rearwardly extended positions by Certain types of these flaps, however, cause a the adjacent vertical fins. These fin or disc surrelatively large rearward shift in the center of faces contribute materially to the directional lift of the wing when the flap is extended rearstability of the airplane particularly when it is wardly, which accordingly presents a problem in of the tail-less or flying-wing type, and being discounter-acting the pitching moment which reposed at the ends of the landing flaps and auxsults when these flaps are placed into use. This iliary balance surfaces serve as efficient tip disturbance to the location of the center of lift shields for the latter thereby contributing imain conventional type aircraft having rearwardly terially to their effectiveness. disposed horizontal tail surfaces is readily com- It is, accordingly, a major object of the prespensated for by producing a negative lift, or ent invention to provide a control system which downward force, by corrective movement of the includes auxiliary balance surfaces which elimielevator surfaces. nate the bucking or nose-heaviness of an aircraft In such conventional empennage type aircraft, when the flaps are placed into use. A corollary these flaps usually produce a down-Wash effect objective is the provision of an auxiliar control which, as it strikes the stabilizer surfaces, also surface disposed between a pair of vertical disc tends to counter-balance the diving moment and or fin surfaces for use in a tail-less type aircraft. thereby produces a more stable longitudinal con- It is a further object to provide an auxiliary baldition. The necessity for this negative lift in ance surface which is completely faired into the the tail surfaces, however, regardless of how it upper surface of the wing when not in use and is developed, adds to the load or the lift which which, when extended rearwardly and upwardly is required to be developed by the main sustaintogether with the flap extension, serves as an ing surfaces. To this extent it has been found elevator means to counteract diving tendencies objectionable and has detracted from the aerocaused by the extension of the flaps. It is a still dynamic efficiency and loading characteristics of further object to provide such an auxiliary elethe airplane. Numerous attempts have been vator surface with means for controlling its made in the past to overcome these disadvantages angle of attack as well as to provide suchsurby the provision of auxiliar lifting surfaces 10- 5 faces with movable trailing portions.

Ga d forwardly With respect o he e er Of It is, accordingly, a further object of the presr vity of the airplane, or the center of pressure ent invention to provide a control surface which ofthe main sustaining surface, in order that this may be umized as combjned.afleron auxiliary lift might assist the lift of the main vator during the take-off and landing of tail-less sustaining s rf r r h o unnecessarily aircraft. A still further object of this invention add to P loadresides in provision for the lateral control of a In tall-less flymgjfimgr types 0f alrcmft tail-less aircraft in flight by the utilization of however the use of i j type fiaps has the said trailing control surfaces, in their re- Problems for Wmch so1ut1ons cannot be tracted positions as a spoiler means to augment Egg1'32.5313 8113121513rdglgrggcglgelr'llgg 22522 52353 whatever aileron control might be provided. A tic: accordingly is directed more iaarticularly to further Object resides in the provision of Such the provision of a novel circular fin and assocontrol Whlch clears the1oWeruface ciated balance or control surface for counterof the trajflmg edge of Structural comphca acting the diving moments produced in both and permlts use of fun 9 flaps and empennage and taiHesS type aircraft upon reap lar controls, which would be interrupted onl-yby Ward extension of the high lift Wing fiaps These the vertical fins. A still further obJect of the ncircular disc or fin urfaces are preferably vervention is the provision of a control surface which tically disposed and may either be fixed with is capable of cooperating with the flaps of a tailrespect to the wing structure or may be rotated less aircraft in such manner that it automatically such that they move between their retracted and extended positions with a uniform clearance between their ends and the inner surfaces of the fins I l and I5. Referring now to Figs. 2 and 3, the fin I 5 is mounted for rotation upon the pivot I6 which is supported from the wing structure. The periphery I5a of the fin is disposed slightly rearwardly of the rear spar Ho and the wing is provided with a cutout portion I II) within which the fin i adapted to rotate with a minimum clearance. .Attached to, and extending rear- Fig. 3 is a cross sectional view. taken along the lines IIIIII of Fig. 2. .looking. toward the f same fin and structure .as taken along the lines VII-VII of Fig. 6; and

.Fig. 8 is a similar sectional view of the control mechanism at the fin pivot.

Referring now to Fig. 1, there is fragmentarily shown a perspective view of an all-wing or tailless type aircraft having a central fuselage or .body in with a nose or cockpit control portion Illa and a fuselagetrailing portion Ib. Extending transversely in the usual manner to either side of the fuselage Ifl, are the main sustaining surfaces or wings having a trailingedge IId which has been shown as sweeping back rearwardly to meet the'trailing portion of the fuselage at IIIb. While the invention has been shown and described as applied to a tail-less. type airplane, it will be understood that it is also capable of use with conventional aircraft having empennages or tails.

The outer portion of each wing is preferably provided with an aileron I2 of the usual type and an inner section of each wing is provided witha high lift fiap I3. Vertical discs or fins It and I of circular plan-form are disposed at each end of the flap I3, being mounted for rotation upon transverse axes within the trailing portion of. each wing. In the modification which has beenselected for illustrative purposes, the trailing edge (I of thewing has been shown as tapering, or being swept forward toward the wing tips. For this reason it will be obvious that, while the vertical fins I4 and I5 lie in parallel vertical planes, the fin I5 lies somewhat more rearwardly of the fin I4 and the central axis of its pivot I6 projected outwardly would strike the plane of the outer fin I l somewhat rearwardly I .portion I8 is pivotally mounted at I9 upon the fins I4 and I5in such manner that as the fins arev rotated in the clockwise direction, as viewed in Figs. 1 and .3, the surfaces I'I-I8 are moved from a recess Ila in the upper surface of the wing II to their upward and rearward operative position'shown in these figures.

As in the case of the flap I3 the ends of the surfaces I!I8 are also cut off at an angle, as indicated in Fig. 2,

wardly from the rear spar IIc are the brackets and 2|, the. upper bracket 20 of which is shownto an .enlarged scale in Figs. 4 and 5. This bracket has an apertured flange portion 20a through which it is attached to the web of the spar Ho and the rearwardly extending portions .of each bracket 20 and 2| has pivotally mounted thereon the staggered guide rollers 22 and 23 respectively, which extend into the slotted guide tracks I41) and I5b of the fins I4 and I5, respectively. These guide slots I41) and I51) are provided with properly placed terminal stops or ends, such as I50 and I50; of the fin I5 shown in Fig. 3, which strike against the rollers 22 or 23 to determine the extreme position of the fin at which the surfaces I'II8 are either retracted or fully extended.

As may be seen in Figs. 6 and 7, the pivot shaft 2 3 for the fin I4 is journaled within the flange pivot hub fittings 25 and 26 which are rigidly fastened to the structure of the wing II. The flange portions of these fittings extend forwardly and are stiffened and braced from the spar He by means of the triangular shaped horizontal brackets comprising the web portions 2'! and 28 and the flanges 21a and 28a, respectively. Mounted for rotation upon the pivot haft 24 and rigidly interconnected with the fin structure I4 is the bell crank member 29 which is attached to the push rod 30 by the pivot SI. The member 29 extends through the bore of the hub fitting 26 and has rigidly attached thereto the lugs or ears 32 which are fixedly attached to the internal structure of the fin It. Suitably keyed to the extending portion of the shaft 24 is a sprocket 34 engaged by the chain 33 which extends forwardly into the .wing structure for operative control by the pilot. There is also keyed to the inner portion of the shaft 24 a sprocket 35 which is adapted to operate, through a chain, such as 36a in Fig. 3, and 36 in Fig. '7, a sprocket 37a (Fig.

.3) mounted upon the pivot I9 for control of the trailing edge surface I8 of the combined aileronelevator I'I. Similar counterparts of each drive are preferably disposed Within each of the fins I4 and I5, there being a like drive chain 33a en- ...gaging a similar sprocket on the-pivot shaft I6 in the fin I5, and a like sprocket 35a driving the chain 36a, as previously described. Returning again toFigs. 6 and 7 with respect to the outer fin I 4, it will be noted that the previously referred to hell crank member 29 has an arm portion fixedly attached thereto as shown in Fig. 8 and ispivotally connected to the push-pull rod 30 at the pivotal connection 3|. It will accordingly be noted that as the forwardly extended push-pull rod 36 is extended rearwardly, through the full line vertical position shown in Figs. '7 and 8, to its rearward dotted position, the disc or fin I4 will have been rotated from the extended position of the surface I'II8 to the retracted position in which these surfaces are faired into the upper surface cavity IIa of the wing II.

Similarly it will be noted that as the chain sections 33 and 3311 are moved under the pilot's control, the corresponding pairs of sprockets 3434a and 35-35a will cause the respective chain strands 36 and 36a to impart corresponding rotation to the trailing edge control surface I8, as by the sprocket'3'la. Referring to Figs. 2 and 3, it will be noted that the leading edge of the surface I1 is provided with a pivotal connection at Ila to an arm 38 which is pivotally connected at 39 to an operating lead screw 40. The

lead screw 40 is provided with a nut member 39 which serves as the pivotal connection adapted to receive the lower terminal of the link or radius rod 38. The lead screw 40 is connected through conventional universal joints to a rotating control rod 4! which extends forwardly to a suitable pilot control means. It will accordingly be noted that as the shaft or rod 4| is rotated, imparting corresponding rotation to the lead screw 49, the nut member 39 in being translated along the axis of the lead screw 40 imparts either upward or downward movement to the radius rod 38 and corresponding change in angle of attack of the aileron-elevator surface [1.

Normally theposition of the pivot nut member 39 is such that as the finsare rotated, and the surfaces l'|l8 projected, the chord of this combined auxiliary surface will be parallel to that of the main airfoil. This combined auxiliary surface forms an airfoil section which is inverted or opposite to that of the normal lifting airfoil inasmuch as this auxiliary surface is intended to normally provide a negative lift. Since the lower terminal of the radius rod 38 is adapted to rotate about its pivotal connection at 39, the upper surface of the wing II is suitably recessed surface operated by the pilot. In certain installations longitudinal flaps would preferably be supported by a vertical fin with one end of the inner flap supported on an extension arm similar to that which is utilized for operating the fin itself. Also if desirable, the vertical fins could be used to carry the auxiliary surfaces such as rudders 0r flaps on the underside of the wing. In

the airplane shown in the drawings, the directional control means would preferably be in the form of wing tip rudders, but it will be understood that the present invention is adapted for use in at H as shown in Fig. 2 to permit retraction of the radius rod into the retracted position shown in Fig. 3 as the auxiliary surface l'l- -lB is housed and faired within the *upper surfaoe'of the wing II. In the latter position the trailing portion l8 of the auxiliary surface is adapted to be rotated into its dotted position by suitable operation of the chains 33 and 33a to serve as a spoiler and to augmentthe aileron action. The mechanism 29-30-3l and 32 for rotating the fins is preferably interconnected with the actuating mechanism for extending and retracting the fiap [3 such that as the flap is extended the auxiliary surfaces l1-l8 are correspondingly extended at the proper angle of attack toi'balance the nose-down moment created by the flap I3.

It is also contemplated that two or more pairs of circular fins, bearing between them longitudinal auxiliary control surfaces, might be installed in certain airplanes. In such arrangements the inner pair on-each wing would be set-and designed to co-act with the flaps for automatically eliminating any pitching or bucking tendencies which might be developed. The outer pair would be used to support a combination aileron-elevator of the type shown'for'both landing'and take-01f. These arrangements are particularly. advantageous in tail-less'aircraft inasmuch as sufiicient control is not normally available togive instant response at lowerspeeds. Once theaircraft were in the air, however, and flying at higher speds, the control problem would not be so critical and the surfaces could be retracted. Under such cruising and high speed flight conditions, it would be possible to maintain longitudinal control with aircraft havin any suitable form of directional control means.

Other forms and modifications of the present invention, which may occur to those skilled in the art after reading the present description, are intended to come within the scope and spirit of this invention as more particularly set forth in the appended claims.

I claim:

1. In an aircraft having a wing, and a fiap operatively associated with said wing subjecting the aircraft in its lift increasing position to a diving I moment, means for counter-balancing said diving moment comprising a pair of vertical fins rotatively mounted upon said wing, said fins pivotally mounted to extend above and below said wing in all rotated positions, a control surface pivotally suported from said fins, and control means for adjusting said control surface both with respect to said wing and to said fins for said wing in all of its rotated positions, a control surface pivotally supported from said fins, and

means for simultaneously rotating said fins and moving said control surface into an operative position arranged for the counter-balancing of the diving moment created by said flap extension.

3. In an aircraft, a wing, a rearwardly extendible fiap operatively associated with said wing arranged upon extension to increase the lift of said wing and to impart a diving moment to the aircraft, a vertical fin rotatively mounted upon said wing in such manner that it extends both above "and below said wing in all of the positions into which itis rotated, a control surface operatively carried upon an upper forward portion of said fin in which position said control surface is retracted within the upper surface of said wing and control means connected to said fin for rotating said fin upper forward portion rearwardly for the rearward and upward extension of said control surface to a position in which it is supported from fin above the trailing edge of said wing.

4. In an aircraft, a wing, a flap operatively associated with said wing, and means for counterbalancing center of pressure shift due to said flap vertical fins and control means for partially rotating said fins for the concurrent extension and retraction of said control surface simultaneously with the extension and retraction of said high lift flaps.

5. In an aircraft, a wing, a flap operatively associated with said win arranged upon extension to increase the lift of said wing and to-causeza center of pressure shift in the wing lift, means for counter-balancing said center of pressure shift comprising a pair of circular vertical fins rotatively mounted upon said wing upon fixed axes such that said fins remain in a relatively fixed position with respect to said wing during their rotation, a control surface pivotally supported by said fins, a radius element pivotally interconnecting said wing and said control surface in such manner that upon rotation of said fins and rearward extension of said control surface said radius element imparts rotation to said control surface about its pivotal support upon said fins into a predetermined attitude substantially parallel with respect to said wing.

6. In an aircraft wing having a fiap operatively associated therewith, means for'counterbalancing center of pressure shift due to said flap actuation comprising a pair of vertical fins rotatively mounted upon a fixed axis in such manner that said fins maintain the same relative positions with respect to said wing during their rotation, a control surface pivotally supported by said fins on a pivot axis spaced from the axis of rotation of said fins, operating means for concurrently extendin said flap and rotating said fins for the simultaneous rearward and upward movement of said control surface to an extended position spaced above the trailing portion of said wing and disposed in asubstantially parallel relationship thereto, and control means for adjusting said control surface in said extended position.

7. In an aircraft wing having a high lift flap operatively associated with a trailing portion thereof, means for counterbalancing-center of pressure shift due to said flap actuation comprising a pair of spanwise spaced vertical fins rotatively mounted upon said wing in such manner that said fins maintain the same relative positions with respect to said wing during rotation, a control surface pivotally supported by said fins on a pivot axis spaced from the axis of rotation of said fins, operating means for concurrently extending said flap and rotating said fins for the extension of said control surface and a radius element housed entirely within one of said fins pivotally interconnecting said wing and said control surface in such manner that upon rotation of said fin and rearward extension of said control surface, said radius element maintains said control surface in predetermined attitudes with respect to said wing.

8. In an aircraft wing having a high lift flap operatively associated therewith, means for counterbalancing center of pressure shift due to said flap actuation comprising a pair of vertical fins disposed at each end of said flap and rotatively mounted upon said wing, a control surface pivotally supported from and extending between said vertical fins, said control surface having an adjustable trailing portion, means for rotating said fin for the upward and rearward extension of said control surface, radius link means pivotally interconnecting said control surface and said wing for predetermined positioning of said control surface with respect to said wing in the said extended position, operating means housed within said fin for the adjustment of said trailing portion of said control surface and means for adjusting the length of said radius link means for adjusting the said relative position of said control surface with respect to said wing.

9. In an aircraft wing having a high lift fiap operatively associated therewith, means for counter-balancing center of pressure shift due to said flap actuation comprising a pair of vertical fins rotatably mounted upon fixed axes in such manner that said fins maintain their relative positions with respect to said wing during rotation of said fins, a control surface pivotally supported by said fins, a recess in the upper surface of said wing arranged to receive said control surface in a retracted position in which the upper surface of said control surface is substantially flush with the upper surface of said wing, said control surface having an adjustable trailing portion, actuating means for rotating said fins in such manner that said control surface is projected upwardly and rearwardly from said retracted position with respect to said wing, and control means for adjusting the said trailing portion of said control surface in both its retracted and extended positions.

10. In an aircraft wing having a flap operatively associated with the trailing portion thereof, means for counter-balancing center of pressure shift due to said flap operation comprising a pair of spanwise spaced vertical fins mounted upon said wing, a control surface pivotally supported at its ends from said fins, a recess in the upper surface of said wing arranged to receive said control surface in its retracted position, said control surface] having an adjustable trailing portion actuating means housed within said fins for projecting said control surface upwardly and rearwardly with respect to said wing, control means housed within said fins for adjusting the said trailing portion of said control surface upwardly in both its retracted and extended positions and further control means operatively associated with said control surface andv extending through said fins for the adjustment of the angle of incidence of said control surface in its extended position with respect to said wing.

11. In an aircraft wing having a flap downwardly and rearwardly extendible from the lower surface thereof, means for counter-balancing the center of pressure shift due to said flap extension comprising an upwardly and rearwardly extendible auxiliary surface co-extensive with the spanwise dimension of said flap, and a pair of spanwise spaced fins mounted upon said wing such that they extend above and below said wing and provide end tip shields for said co-extensive fiap and auxiliary surface.

12. In an aircraft wing having a flap operatively associated with the lower surface thereof, means for counter-balancing center of pressure shift due to said flap operation comprising a pair of laterally spaced fins pivotally mounted upon a fixed axis such that they maintain the same relative positions with respect to said wings, a balance surface pivotally supported by said fins on a pivot axis spaced from the axis of pivotation of said fins, operating means for rotating said fins for. the extension of said balance surface into its operative position for the counter-balancing of the center of pressure shift caused by said fiap actuation, mechanism associated with the leading edge of said balance surface for the adjustment of its angle of attack in its extended position, said balance surface having a pivoted trailing portion and mechanism for adjusting said trailing portion with respect to said balance surface.

13. An aircraft wing, a flap operatively associated with the lower surface of said wing, a pair of vertical fins rotatably mounted upon fixed axes housed within the trailing portion of said wing in such manner that said fins maintain the same relative positions with respect to said Wing during rotation of said fins, a control surface disposed above said wing trailing portion pivotally supported by and extending between said fins, said fiap and said control surface being substantially co-extensive in the spanwise direction such that said fins are abutted by said flap and control surface and form tip shields for said fiap and said control surface in each of their retracted and extended positions, and actuating mechanism for simultaneously extending and retracting said flap and said control surface.

14. In an aircraft wing having a flap operatively associated with the trailing portion thereof, means for counter-balancing center of pressure shift due to said flap operation comprising a pair of vertical fins rotatably mounted upon said wing, a control surface pivotally supported by said fins and eccentrically disposed with respect to the axis of rotation of said fins, a recess in the upper surface of said wing arranged to receive said control surface in its retracted position, said control surface having an adjustable trailing portion, means for rotating said fins in such manner that said control surface is projected upwardly and rearwardly with respect to said wing while said fins maintain the same relative position with respect to said wing, means for adjusting the said trailing portion of said control surface upwardly in both its retracted and extended positions and further control means operatively associated with said control surface for the adjustment of the angle of incidence of said control surface in its extended position with respect to said wing for counterbalancing said center of pressure shift due to said fiap operation.

15. In an aircraft wing having a fiap extendible from the lower surface thereof, counterbalancing means for compensating for the center of pressure shift due to said fiap extension comprising an auxiliary surface co-extension with the spanwise dimension of said fiap extendible from the upper surface of said wing, a pair of spanwise spaced fins mounted upon said wing such that they extend above and below said wing and provide end tip shields for said co-extensive flap and auxiliary surface, and actuating means for simultaneously extending and retracting said fiap and auxiliary surface.

16. In an aircraft wing having a fiap extendible from the lower surface thereof, counterbalancing means for compensating for the center of pressure shift due to said flap extension comprising an auxiliary surface co-extensive with the spanwise dimension of said fiap extendible from the upper surface of said wing, a pair of spanwise spaced fins mounted upon said wing such that they extend above and below said wing and provide end tip shields for said co-extensive flap and auxiliary surface, actuating means for simultaneously extending and retracting said fiap and auxiliary surface, and mechanism extending from said wing through said fins to said auxiliary surface for controlling the angle of incidence of said auxiliary surface in its extended position.

WILLIAM I. TINDALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,774,474 Burnelli Aug. 26, 1930 2,120,760 Lumiere June 14, 1938 2,218,822 Joyce Oct. 22, 1940 2,252,656 Youngman Aug. 12, 1941 2,271,763 Fowler Feb. 3, 1942 2,383,102 Zap Aug. 21, 1945 

